/*
 * Copyright 2007-2008 Sun Microsystems, Inc.  All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.sun.swingset3.utilities;

import java.awt.Component;
import java.awt.Cursor;
import java.awt.EventQueue;
import java.util.EventListener;
import javax.swing.JEditorPane;
import javax.swing.event.HyperlinkEvent;
import javax.swing.event.HyperlinkListener;
import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.Element;
import javax.swing.text.StyleConstants;
import javax.swing.text.View;
import javax.swing.text.ViewFactory;
import javax.swing.text.html.HTML;
import javax.swing.text.html.HTMLEditorKit;
import javax.swing.text.html.ObjectView;

import com.sun.swingset3.demos.DemoUtilities;

/**
 * 
 * Extends JEditorPane for more convenient display of an HTML page.
 * <p>
 * Swing's HTML support allows Swing components to be embedded in the HTML using
 * the <object> tag, e.g.<br>
 * 
 * <pre>
 * &lt;code&gt;    
 * &lt;object classid=&quot;swingset3.demos.controls.JButtonDemo&quot;&gt;
 * &lt;/code&gt;
 * </pre>
 * 
 * These embedded components will be instantiated deep inside the text package
 * and it is difficult to get a handle on the resulting instantiated component
 * instance. Thus, this class supports adding a ComponentCreationListener to be
 * notified just after the component is created.
 * </p>
 * <p>
 * This class also automatically installs a hyperlink listener to ensure that
 * clicking on hyperlinks bring up the associated url in the browser.
 * 
 * @author aim
 */
public class HTMLPanel extends JEditorPane {
	/**
	 * Callback interface for getting notification when components specified in
	 * the <object> tag are created in the editor pane.
	 */
	public static interface ComponentCreationListener extends EventListener {
		public void componentCreated(HTMLPanel htmlPanel, Component component);
	}

	private static HyperlinkHandler hyperlinkHandler;

	/**
	 * Creates a new instance of HTMLPanel with a default content type of
	 * &quot;text/html&quot;
	 */
	public HTMLPanel() {
		setContentType("text/html");
		setEditorKit(new ComponentEditorKit()); // brute force
		setEditable(false); // VERY IMPORTANT!
		if (hyperlinkHandler == null) {
			hyperlinkHandler = new HyperlinkHandler();
		}
		addHyperlinkListener(hyperlinkHandler);
	}

	public void addComponentCreationListener(
			HTMLPanel.ComponentCreationListener l) {
		listenerList.add(ComponentCreationListener.class, l);
	}

	public void removeComponentCreationListener(
			HTMLPanel.ComponentCreationListener l) {
		listenerList.remove(HTMLPanel.ComponentCreationListener.class, l);
	}

	private class ComponentEditorKit extends HTMLEditorKit {
		@Override
		public ViewFactory getViewFactory() {
			return new ComponentFactory();
		}
	}

	protected class ComponentFactory extends HTMLEditorKit.HTMLFactory {
		public ComponentFactory() {
			super();
		}

		@Override
		public View create(Element element) {
			AttributeSet attrs = element.getAttributes();
			Object elementName = attrs
					.getAttribute(AbstractDocument.ElementNameAttribute);
			Object o = (elementName != null) ? null : attrs
					.getAttribute(StyleConstants.NameAttribute);
			if (o instanceof HTML.Tag) {
				if (o == HTML.Tag.OBJECT) {
					return new ComponentView(element);
				}
			}
			return super.create(element);
		}
	}

	protected class ComponentView extends ObjectView {
		public ComponentView(Element element) {
			super(element);
		}

		@Override
		protected Component createComponent() {
			final Component component = super.createComponent();

			Runnable notifier = new Runnable() {
				public void run() {
					final ComponentCreationListener listeners[] = HTMLPanel.this.listenerList
							.getListeners(ComponentCreationListener.class);
					for (ComponentCreationListener l : listeners) {
						l.componentCreated(HTMLPanel.this, component);
					}
				}
			};
			// just in case document is being loaded in separate thread. (?)
			if (EventQueue.isDispatchThread()) {
				notifier.run();
			} else {
				EventQueue.invokeLater(notifier);
			}
			return component;
		}
	}

	// single instance of handler is shared for ALL DemoPanel instances
	public static class HyperlinkHandler implements HyperlinkListener {
		Cursor defaultCursor;

		public void hyperlinkUpdate(HyperlinkEvent event) {
			JEditorPane descriptionPane = (JEditorPane) event.getSource();
			HyperlinkEvent.EventType type = event.getEventType();
			if (type == HyperlinkEvent.EventType.ACTIVATED) {
				try {
					DemoUtilities.browse(event.getURL().toURI());
				} catch (Exception e) {
					e.printStackTrace();
					System.err.println(e);
				}

			} else if (type == HyperlinkEvent.EventType.ENTERED) {
				defaultCursor = descriptionPane.getCursor();
				descriptionPane.setCursor(Cursor
						.getPredefinedCursor(Cursor.HAND_CURSOR));

			} else if (type == HyperlinkEvent.EventType.EXITED) {
				descriptionPane.setCursor(defaultCursor);
			}
		}
	}
}
